I don't think that should matter. This test suite is for the Google::Adwords module. When I run the sandbox tests for, say the CampaignService test module, I then require the campaign ids for use in the AdGroupService test module. These are only for the sandbox tests, and I can test the various service modules independently otherwise.

Fair enough. If it were me I'd probably factor out the common code into a separate module that both test classes used, enabling me to run each class independently. But that's just me ;-)